Method of and apparatus for lubricating pneumatic tools



June 17, 1941.

C. A MEDSKER METHOD OF AND APPARATUS FOR LUBRICATING PNEUMATIC TOOLS E.57 E 3 22 "7 8 i N ZZ 27 j I I I /a 59 I 5 Filed Feb. 6, 1939 HHl'llHllINVENTOR.

CHARLES A. MEDsKER BY #044- j? ATTORNE Patented June 17, 1941 METHOD OFAND APPARATUS FOR LUBRICATING PNEUMATIC TOOLS Charles A. Medsker,Cleveland Heights, Ohio, assignor to William L. Ulmer, Cleveland, OhioApplication February 6, 1939, Serial No. 254,761

7 Claims.

This invention relates to a novel method of and apparatus forlubricating pneumatic tools, such as hammers, riveters, rock drills,welding machines and similar power tools utilizing air pressure as theirsource of power.

In my co-pending application, Serial No. 206,414, there is disclosed anapparatus whereby a lubricant, such as oil, in a finely divided,vaporous or suspended form, is entrained in the air pressure supply forpneumatic tools and the like. In that apparatus, the amount andproportion of lubricant entrained in the ultimate air supply deliveredto the tool lines is variably regulated by means of control valvesprovided for this purpose.

It has been found, however, that in cases where the air supply demandincreases to any considerable extent that a drop in the air pressureoccurs ahead of the-valve openings without a corresponding increase inthe pressure behind the valve openings. This results in an undesiredvariation in the amount of oil entrained in the air, and makes itnecessary to frequently adjust the valves in order to compensate for thevaria tion in pressure and maintain the desired differential between thepressures ahead and behind the valve openings, which, in actualpractice, should be approximately pounds. Such adjustments are not onlydifficult, but are time-consuming as well.

It is a primary object of the present invention to provide incombination with apparatus of the aforesaid character valve mechanismwhereby a constant differential is maintained between the pressuresahead of and behind the valve openings and whereby uniformity in theair-oil ratio is maintained at all times irrespective of the demandsmade upon the apparatus.

To the accomplishment of the foregoing and related ends, said invention,then, consists of the means hereinafter fully described and particularlypointed out in the claims; the annexed drawing and the followingdescription setting forth in detail certain means of carrying out theinvention, such disclosed means illustrating, however, but one ofvarious ways in which the principle of the invention may be used;

In said annexed drawing Fig. 1 is a vertical cross-sectional viewthrough the apparatus; and

Fig. 2 is an enlarged cross-sectional view of the valve mechanismillustrated in Fig. 1.

Referring more particularly to the drawing, the apparatus will be seento comprise a container I into which the main air pressure supply isintroduced through the inlet 2. This inlet is provided at its lower endwith a cylindrical screen 3 for entrapping dirt and other foreign matterin the air supply,

The container has a horizontal dividing wall 4 which separates theinterior of the container into an upper moisture and foreign particleeliminating or precipitating compartment and a lower oil entrainingcompartment. Excess moisture and foreign particles entrained in the airsupply are precipitated and eliminated in this upper chamber, due to theincrease in volume or expansion of the air stream and also its change indirection of flow.

A pipe or conduit 5 leads from the upper portion of the upper chamber ofthe container I, through the wall 4, to the lower portion of the lowercompartment of the container, where it connects with an elbow 5. To thiselbow is joined a check valve 1, which prevents reverse or flow back-upfrom the oil entraining compartment. To the other end of the valve 1 issecured an elbow 8, which rests on a perforated baffle plate or screen 9extending across the oil entraining compartment and spaced somewhat fromthe bottom of the container.

A conduit H] having a screen H on its lower end, extends from the upperportion of the oil entraining compartment through the wall 4 and uppercompartment of the container through the upper wall of the container andhas fitted to its upper end a reducing elbow I2. I

The upper end of the conduit 5 has mounted thereon a cylindrical screenl3, so that the air entering this conduit must pass through this screen.Another conduit l4 leads from the upper end of the screen l3 through theupper wall of the container and has connected to its upper end areducing elbow l5, from which extends a nipple I 6. This nipplecommunicates with the inlet opening ofa pressure regulating and reducingvalve, which has been generally designated by the reference numeral H.

The reducing valve [1, as best shown in Fig. 2, comprises a body 18,having an inlet opening IS an an outlet opening 20, the outlet openingcommunicating with a conduit 2|, from which branch lines, not shown, maylead to the individual pneumatic tools. The valve body l8 has securedthereto a cover 22, and a diaphragm 23 is interposed between the bodyand cover. The body has secured in its lower central portion a plug 24,in which is slidably mounted a valve stem 25 which cooperates with thevalve seat 25, the valve stem being urged against its seat by means of acoil spring 21. The valve stem 25 establishes communication between theinlet l9 and the valve compartment 28 below the diaphragm 23, and thecompartment 28 in turn is in communication with the outlet opening 2!!by means of a passageway 29.

The cover 22 has an axial bore 30 therein, in which is disposed a coilspring 3| which bears l at its upper end against a washer 32 secured tothe lower end of a screw 33 in threaded engagement with a plug 34. Alock nut 35 is mounted on the screw 33 to lock it in adjusted position.The lower end of the spring 3| bears against a washer 3'5 which issecured, as by nuts 31, to an eXtension 3S of the valve stem 25.

Secured to the lower end of the valve stem 25 is an opener element 39having a reduced lower end Ml which bears against the needle 4| of aneedle valve 22 secured to the plug in axial alignment with the latter.The valve 42 has a tapered seat 43 therein against which the needlebears when the valve is closed. The needle 4| has an enlarged baseportion "is and a spring 45 is interposed between this base portion anda plug it secured to the lower end of the valve. A conduit t?establishes communication between the reducing elbow l2 and the valve42.

An oil filler pipe 59 is also provided for admitting oil into the lowercompartment of the container.

Vents 5i and 52 are located in the side wall of the container l and incommunication with the upper and lower chambers, respectively. Draincocks 53 and 5 are also connected to the bottoms of each one of thesetwo chambers. An oil test cock 55 is also mounted in the side wall ofthe container for ascertaining when the oil is at the desired level.

The operation of the above described apparatus is as follows: The mainair supply is introduced through the inlet 2, and passes into the upperchamber of the container, where excess moisture and foreign particlesare precipitated. This air supply then follows the direction of thearrows through the screen i3 and thence the stream is divided to theconduits and ii. That portion of the air stream going through theconduit 5 passes up through the bath of the lubricant or oil in thelower chamber of the container 1 where it entrains particles oflubricant in the form of a fog or a vapor, and such lubricantcontainingair then enters the conduit NJ and passes into the reducing valve H byway of the elbow l2, conduit ll, and valve 42, where it is mixed withthe remainder of the air stream from conduit l4, and nipple Hi.

The reducing valve I! automatically serves to maintain a constantpressure dilferential between the air entering the valve and thatleaving the valve. Thus, if the pressure at the outlet drops due to aheavy increase in the demand, the spring 3! forces the valve open,thereby restoring the out-going pressure to its original value withinthe limits of the main air supply pressure. If the outgoing pressureincreases, the diaphragm is forced against the spring and the valvecloses. By screwing down the adjusting screw 33 the low pressure isincreased, and by releasing the screw, the low pressure is decreased.The valve is preferably set at pounds below the main air supply linepressure, so that a 10 pound differential is maintained at all timesirrespective of the air demand.

Due to the operation of the valve 42 simultaneously with that of valveH. the pressure in the air-oil mixing chamber will be regulated in thesame manner as that in the air line.

Since the valve 97 opens and closes according to the demand, and sincethe valve 42 is actuated by the valve 17, the proportion of the air-oilmixture to the air is determined by the simultaneous movement of the twovalves. Since the ratio is fixed, the final air-oil mixture is constantirrespective of the outlet demand for air.

Other forms may be employed embodying the features of my inventioninstead of the one herein explained, change being made in the form orconstruction, provided the elements stated by any of the followingclaims or the equivalent of such elements be employed.

I therefore distinctly point out and distinctly claim as my invention:

1. In apparatus of the character described, the combination of a sourceof air under pressure, means for dividing said air into two streams,means for entraining a lubricant in one of said air streams, and meansfor reuniting said lubricant-entraining air with said other stream, saidlast-named means comprising a valve and means associated with said valvefor maintaining a uniform pressure difierential between the mixtureentering said valve and that leaving said valve.

2. In apparatus of the character described, the

combination of a source of air under pressure,

means for dividing said air into two streams, means for entraining alubricant in one of said air streams, a Valve for receiving saidlubricantentraining air stream along with said other air stream, and asecond valve actuatable by said first valve for controlling the amountof lubricant-entraining air stream admitted to said firstnamed valve.

3. The method of preparing lubricant-entraining air for the operation ofpneumatic tools, which comprises dividing an air stream into two parts,entraining a lubricant in one of said air streams, reuniting saidlubricant-entraining air with said other air stream, and automaticallymaintaining the proportion which each division of said air stream bearswith respect to the other, irrespective of the demand of said toolswithin the limits of the pressure of said first-named air stream.

i. In apparatus of the character described, the combination of a sourceof air under pressure, means for dividing said air into two streams.means for entraining a lubricant in one of said streams, means forreuniting said lubricant-entraining air with said other stream, andmeans for automatically maintaining the pressure of the mixture at asubstantially predetermined value irrespective of the number of tools towhich the mixture is conveyed.

5. In apparatus of the character described, the combination of a sourceof air under pressure means for entraining a lubricant in said air, avalve for controlling the flow of said lubricant entraining air, andresilient means for urging said valve open.

6. In apparatus of the character described, the combination of a sourceof air under pressure, means for entraining a lubricant in said air, avalve for controlling the flow of the lubricant entraining air,resilient means for urging said valve open, and means responsive to thepressure in said valve for counter-acting said resilient means.

7. In apparatus of the character described, the combination of a sourceof air under pressure, means for dividing said air into two streams,means for entraining a lubricant in one of said streams, and means forreuniting said lubricantentraining stream with said other stream, saidlast-named means comprising a chamber, a valve for controlling the flowof one of said streams to said chamber, the other of said streams beingfree to flow to said chamber, and means for releasing said reunitedstreams from said chamher and for controlling said valve.

CHARLES A. MEDSKER.

